According to the World Health Organization, each year, up to 650,000 people die from respiratory illnesses related to seasonal flu. 650,000 people. Every year. And yet, we’re still not able to create a truly universal flu vaccine. At least until today: when a messenger RNA-based vaccine can change everything.
What happens to us with the flu? That it is a difficult disease. All the diseases that have been eradicated (smallpox and rinderpest) or “candidates for disappearance” (malaria, dracunculiasis, yaws and, above all, polio) have certain things in common, but there is one that is capital: their natural reservoir is only and exclusively the human being (or, in the case of diseases such as rinderpest, the animal reservoir is a single easily identifiable species).
In other words, with our current technological, health and social development, we can only deal face to face with diseases that have difficulties in overcoming interspecies barriers and that are not difficult to follow in open ecosystems. The flu is the opposite.
It is a disease with an amazing ability to jump between birds, horses, pigs, humans and back again. And not only that, it is a disease with a surprising capacity to generate new subtypes. And it is precisely this that makes making a universal efficient vaccine a biotechnological hell.
but we have vaccine. Yes it’s correct. We have flu shots. And designing, producing and placing them is one of the most ambitious health programs that have been carried out in the history of humanity. But the unheard of is not that; the unheard of thing is that we do it every year.
Every year, the network of monitoring centers that the World Health Organization has around the world tries to determine which strains are circulating in different societies and which have the greatest potential to become epidemic. With this prediction, hundreds of laboratories around the world are launching into the manufacture of a vaccine that normally has an effectiveness of between 40 and 60% (although there are years, such as 2018, that does not reach 25%). Hence, the search for a universal vaccine has been a constant.
A universal vaccine? As I write, dozens of research groups around the world are seeking what is known as the universal flu vaccine. That is, the identification of some factor of the virus that is stable enough across all subtypes to be used with it: finding it would simply change the playing field completely.
The idea sounds so good and is so attractive that even moguls like Larry Page, co-founder of Google, have jumped on the search. But it has been impossible. The virus’s prodigious ability to mutate always finds a way to outwit our attempts. This is where the messenger RNA comes in.
mRNA vs flu. As explained today in ‘Science’, Claudia Arévalo and her team have managed to develop a lipid mRNA nanoparticle vaccine that contains antigens from the 20 known subtypes of influenza A and B viruses. In other words, all possible subtypes and variants of the virus from the flu. And when I say all, it means all. As Víctor Jiménez Cid, professor of parasitology at the UCM, explained in SMC, “this type of vaccine would prevent, in addition to seasonal flu, avian flu infections in humans, which has a mortality rate of close to 30%, and possible new pandemic viruses emergent”.
Preclinical studies (in experimental models) are very promising. Although, as Adolfo García-Sastre, director of the Institute for Global Health and Emerging Pathogens at Mount Sinai Hospital in New York, pointed out, “although they suggest protective capacity against all subtypes of influenza viruses, we cannot be sure of this until it is do clinical trials on volunteers.
What impact does this have?. If confirmed, revolutionary. Because, as Estanislao Nistal, a virologist and CEU San Pablo University, pointed out, not only “implies that it is possible to potentially have a universal vaccine that is easy and quick to build” but that “this vaccine could also be very useful in preventing influenza in animals that can suffer from it, and reduce the risk of zoonoses among animals in a context of global health”. Avian flu, as we have seen recently, is a major economic problem for the agricultural sector.
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